An investigation into the vibration of harmonic drive systems

Masoumi, Masoud; Alimohammadi, Hossein

doi:10.1007/s11465-013-0275-5

“…However, this method requires many parameters to be tuned, which is not conducive to the control of variable load models [13]. Su et al used the ESO to estimate and compensate the nonlinear and uncertain parts of the stiffness and damping of the rigid-flexible coupled platform, but this method requires many parameters to be tuned [14][15][16].…”

Section: Related Workmentioning

confidence: 99%

A Dual-Position Loop LLADRC Control Method Based on Harmonic Gear Drive

Yu

¹

,

Wang

²

,

Li

³

et al. 2022

Mathematical Problems in Engineering

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High-resolution imaging has become a development trend and is widely used in military and civil fields. As the carrying equipment of imaging system, the speed stability of tracking turntable is the basis of high-resolution and stable imaging. At present, in the aerospace field, there are high requirements for peak power dissipation and holding torque, so flexible joints such as harmonic gear drive are mostly used to realize the function. The characteristics of flexible load have a great impact on the characteristics of motion control, which is easy to cause mechanical resonance, lead to system instability, and have a great impact on speed stability and position tracking accuracy. Therefore, it is necessary to study the servo system of flexible load. In order to solve the problems of high-precision position control and speed stability at low speed of flexible turntable with uncertain load, on the one hand, we comprehensively consider the advantages and disadvantages of semi-closed-loop and full closed-loop control and design a dual-position loop feedback control system combined with the analysis of dynamic equation to realize speed stability and high-precision position control. On the other hand, according to the requirements of the speed stability at low speed of the turntable, the tracking differentiator (TD) is designed innovatively through the language three-point interpolation subdivision and five-point pre-deduction calculation method. Finally, a dual-position loop LLADRC (language linear active disturbances rejection controller) control method based on harmonic gear drive is studied. By comparing the semi-closed loop, dual-position loop, dual-position loop LADRC (linear active disturbances rejection controller, ADRC), and dual-position loop LLADRC methods through simulation analysis, it can be shown that the double position LLADRC control method is obviously superior to other schemes in terms of rapidity, speed stability at low speed, and position tracking accuracy. The theoretical research is verified by experimental test. When the given speed is 0.1 ° / s , taking the pitch axis as an example, the pitch speed error is 0.0039 ° / s (3σ). When the maximum speed of the given curve is 20 ° / s and the maximum acceleration is 16 ° / s , the position tracking error is 0.0025° (3σ). This control method solves the problems of system instability and low-speed stability in high-precision control of turntable system based on harmonic gear drive and provides a method for high-precision control of high-resolution imaging turntable.

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“…If the transmission angle error θ is small enough, the motor and load does not contact in the backlash area. The transmission torque of gear train can be rewritten as (Nordin and Gutman, 2002) Figure 3. Stiffness model of anti-backlash gear train.…”

Section: Model Of the Anti-backlash Geared Servo Systemmentioning

confidence: 99%

Design optimization analysis of an anti-backlash geared servo system using a mechanical resonance simulation and experiment

Zhang

¹

,

Liao

²

,

Ding

³

et al. 2021

Mech. Sci.

1

0

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Abstract. In many mechatronic systems, gear transmission chains are often used to transmit motion and power between motors and loads, especially for light, small but large torque output systems. Gear transmission chains will inevitably bring backlash as well as elasticity of shafts and meshing teeth. All of these nonlinear factors will affect the performance of mechatronic systems. Anti-backlash gear systems can reduce the transmission error, but elasticity has to be considered too. The aim of this paper is to find the key parameters affecting the resonance and anti-resonance frequencies of anti-backlash gear systems and then to give the design optimization methods of improving performance, both from element parameters and mechanical designing. The anti-backlash geared servo system is modeled using a two-inertia approximate model; a method of computing the equivalent stiffness of anti-backlash gear train is proposed, which comprehensively considers the total backlash of transmission chain, gear mesh stiffness, gear shaft stiffness and torsional spring stiffness. With the s-domain block diagram model of the anti-backlash geared servo system, the influences of four main factors on the resonance and anti-resonance frequencies of system are analyzed by simulation according to the frequency response, and the simulation analysis results dependent on torsional spring stiffness of anti-backlash gear pair and load moment of inertia variation are verified by the experiment. The errors between simulation and experimental results are less than 10 Hz. With these simulation and experiment results, the design optimization methods of improving the resonance and anti-resonance frequencies such as designing the center distance adjusting mechanism to reduce the initial total backlash, increasing the stiffness of torsional spring and lightweight design of load are proposed in engineering applications.

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“…The following are the advantages of a harmonic reducer: (1) Compared with other reducers, the harmonic reducer has a smaller volume and simpler structure, and it generally consists of three basic components (wave generator, flexible wheel, and rigid wheel) [20]. (2) The harmonic reducer can be used with large loads.…”

Section: System Designmentioning

confidence: 99%

Development of a Rapid Optical Measurement System for Circular Workpieces with Irregular Tooth Contours after Broaching Process

Chen¹,

Liang²,

Ye³

et al. 2020

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During a manufacturing process, it is essential to quickly identify whether a tool needs to be replaced or adjusted, to ensure that production quality is not compromised. Therefore, the re-inspection of the product or first article inspection is an important process. Reducing the inspection time can reduce the time spent waiting for a product in the production line. This research aimed to design a system that can automatically and rapidly measure the dimensions of irregular tooth contours in the broaching process, to ensure cutting tools are replaced when necessary. This study developed an automatic machine for measuring the irregular tooth contours of large ring parts; the tooth root, tooth height, and tooth thickness of the workpiece are measured. The measurement diameter is approximately 200 mm, and the radial inspection accuracy is within ±20 μm; we aimed to reduce the detection time considerably. An optical micrometer and an automatic rotating platform were used in the measurement system. The workpieces to be measured were easy to install, and the eccentricity was automatically corrected by the system, thus saving time that would be taken to correct Abbe errors. This research successfully developed a rapid optical measurement system that can reduce the inspection time from 30 min to 60 s. Moreover, the maximum radial measurement error is −0.02 mm, which means that the measurement accuracy is within ±20 μm (total: 40 μm).

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An investigation into the vibration of harmonic drive systems

Cited by 10 publications

References 14 publications

A Dual-Position Loop LLADRC Control Method Based on Harmonic Gear Drive

A Dual-Position Loop LLADRC Control Method Based on Harmonic Gear Drive

Design optimization analysis of an anti-backlash geared servo system using a mechanical resonance simulation and experiment

Development of a Rapid Optical Measurement System for Circular Workpieces with Irregular Tooth Contours after Broaching Process

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